电化学方法测定氢在TiNi貯氢合金中的扩散系数

在20±0.3 ℃时, 用电化学方法测得氢在TiNi贮氢合金中的扩散系数为(6.45±0.78)×10~(-7)cm~2sec~(-1), 氢在这种合金中扩散过程的活化能为16.59 kJ mol~(-1)。TiNi合金电极在NaOH溶液中, 经过多次电化学渗氢以后, 在合金表面覆盖着一层钛的氧化物, 在这氧化物层的下面为富镍层。

DETERMINATION OF HYDROGEN DIFFUSION COEFFICIENT IN TiNi ALLOY BY ELECTROCHEMICAL METHOD

The diffusion coefficient D of hydrogen in TiNi alloys was determination with electrochemical method at 20±0.3℃. The value of D was (6.45±0.78)×10~(-7) cm~2·s~(-1). (fig.1,2). The activity energy of hydrogen diffusion in TiNi alloy was. 16.59 kJ·mol~(-1) (fig.3). The data of X-ray protolelctron spectroscopy (XPS), auger electron spectroscopy (AES), scan electron microscop (SEM) and energy dispersive analysis of X-ray (EDAX) showed that after charged-discharged hydrogen several cycls by electrochemical method, a layer of titanium oxide which contains no nickel was coated on surface of TiNi alloy electrode, beneath this oxide layer there was a Nickel-rich alloy layer, in which the ratio of titanium to nickel is 1:1.28. Thus we concluded that there is a layer of Nickel metal beneath the oxide coating surface. This results coincide with the conclusion of van waldkirch~15].